The Player Of Games

"Perl Moderne" : a new Perl book

I haven't been blogging a lot this year-and-half, and for various reasons. But the reason number one is that I've been very busy writing a Perl book from scratch, in French, with 3 other fellow French Perl Mongers.

The book is called Perl Moderne. That means "Modern Perl", but it has nothing to do with chromatic's book. The book was actually published long time ago, end October 2010. But it took us authors some time to recover :)

This book is written in French, for French speaking readers. Its goal is to present the Perl 5 language as it exists now, and tries to teach the reader how to start using it the right way, that is, the modern way. The book is not a bible, nor an encyclopedia of the historical language. Instead, it's a collection of the useful concepts that are used nowadays, and how to use them in the latest version of Perl and CPAN.

The reader can be a total newbie in Perl, but it has to have a previous development experience with an other language, for instance PHP, Ruby, Python, or Java. However, the book goes far beyond introducing the language. It allows the reader to become fluent with the Perl data structure, regexps, Moose OO and typing, POE, interacting with databases, files, DateTime, XML and configuration files, Web interactions, and more...

It's big in content (many subjects covered, and 450 pages !) but small in size, as it's an A5 format, so it fits easily in a bag, and it's not heavy :)

The people

Historically, Pearson France, the press editor, posted a request on the French Perl Mongers mailing list, saying that they were looking for authors willing to write a new Perl Book in French.

I decided to not let this opportunity pass : it's very rare that French editors are interested by Perl, and willing to produce good quality books. After some struggling, I ended up setting up a team of 4 brave French Perl Mongers, that became 4 Perl book authors :

• Sébastien Aperghis-Tramoni (SAPER on CPAN) : active French Perl Monger, he knows almost everything about CPAN modules. He wrote several modules himself, and maintains numerous others. He wrote several Perl articles in the GNU/Linux Magazine France. He is also the hidden admin of your Perl conferences, as he maintains Act, empowering a lot of Perl conferences

• Philippe Bruhat (BOOK on CPAN) : well known Perl figure, active French Perl Monger, former president of them, founder and treasurer of the YAPC Europe Foundation. Received a White Camel Award in 2009, and maintains quite a few modules on CPAN. Also wrote articles in the GNU/Linux Magazine France.

• Jérôme Quelin (JQUELIN on CPAN) : active French Perl Monger, knows a great deal about Tk, wrote Games::Risk among other things, and maintains a bunch of CPAN modules. He is also maintaining a lot of Perl packages at Mandriva and Mageia. Also wrote articles in the GNU/Linux Magazine France.

• Damien Krotkine (DAMS on CPAN) : well that's me ! I'm an active French Perl Monger, using Perl for 11 years or so, I wrote a couple of Perl articles in the GNU/Linux Magazine France, have some modules on CPAN (among them Curses::Toolkit), and I'm now a proud core developer of Dancer, the new big thing.

The content

Perl Moderne starts with a gentle (but concise) introduction to Perl, with many pointers to external resources, focusing on ease-of-use. For instance, we mention CPAN and cpanm very early. Then the real business starts with an explanation of the major programming concepts (data structures, OO, databases, formats, event programming and the intarweb).

We tried to provide a preferred way to do each thing, while mentioning alternatives. We didn't separated the language and CPAN. "Perl is the syntax, CPAN is the language"... So about half of the book describes how to solve a problem using this or that CPAN module. And I think it's great. It allowed us to teach Object Oriented programming with Moose, explain event programming with POE, etc.

I think it is very important that new Perl books get written, and very important that some are written natively in non-english. It fits better its purpose to the localized need (students, teachers, academic structures and way of thinking are different from one country to another). That also makes editors aware of the local Perl activity, and help spreads the words about the language in schools and universities, where native books are preferred to translations.

So, if you know any French speaking (or learning) geek or computer scientist, around you, please consider recommending them this book. It was crafted with care and love by Perl passionated ! :) You can point them to the dedicated website of Perl Moderne

 

Here is an english translation of the table of content :

01. Start with Perl
02. Install a Perl module

I. Language and data structures
03. Language
04. Data structures
05. Regular expressions

II. Modern object programming
06. Basic Perl objects
07. Moose
08. Typing system in Moose
09. Methods in Moose

III. Data manipulation
10. Files and directories
11. SQL databases
12. SQL abstraction, ORM, non-SQL databases
13. Dates and times

IV. Formats
14. XML
15. Data serialisation
16. Configuration files

V. Event programming
17. Introduction to POE
18. Practical POE
19. Distributed POE

VI. Web
20. HTML documents parsing
21. HTTP and the Web
22. LWP
23. Web browsing
24. WWW::Mechanize

Perl Dancer and DBIC

Are you curious to see how to create a real app from scratch with Perl Dancer, using DBIX::Class ? Well, my Perl Dancer Advent Calendar article has been published saturday :

http://advent.perldancer.org/2010/11

Enjoy !

Perl Dancer version 1.2 and Advent Calendar

 

Perl Dancer should at least ring a bell to you : it's a popular Perl micro web framework. Route based, easy to use, simple clean design, with low dependancies, Dancer is gaining in popularity and maturity.

Version 1.2 has been released ( see sawyer's announcement here ), and is described as the first stable community release.

But that's not all ! Go check out the awesome Perl Dancer Advent Calendar. You'll learn all about Dancer, how to get started with it, what cool plugins are available, what are the nice tricks. Step by step, a new article will be revealed each day.

Dancer is a young project with a nice community. Check it out :

• http - http://perldancer.org/
• IRC - #dancer on irc.mongueurs.net
• ml - http://www.backup-manager.org/cgi-bin/listinfo/dancer-users

 

Ulimit doesn't work on Leopard (memory limitation)

After many tests on my side, I got confirmation from this page : it looks like ulimit doesn't work for memory limitation starting from Mac OS 10.5. That's a shame...

perl -E 'use BSD::Resource;  setrlimit(RLIMIT_VMEM, 2000, 2000); my $s; for my $i (1..50_000) { $s .= "A" x 1024 } say "damned, I should have been killed"'

 

Merge PDFs easily with Perl

Today Idiscovered an easy way to merge PDFs files using Perl.

In my current project, I have to automatically generate a technical documentation from my perl modules PODs. It's easy to create one PDF file for each modules, but then I need to merge them all in one.

The very easy to use CAM::PDF Perl module provides appendpdf.pl. However it can only merge 2 files together.

I've copied and modified it for my need, and renamed it mergepdf.pl

Download : mergepdf.pl

Usage :  appendpdf.pl [options] file1.pdf file2.pdf ... fileN.pdf outfile.pdf

See the help for more options.

Typepad

I'm in the metro of Paris, testing Typepad :

• new beta account I just subscribed to
• new mobile version of the blog
• Iphone App
• automatic Twitter posting
• per category feeds

Typepad is Based on Movable Type, the best blog system ouuta there. It's Perl based. It rocks.

Perl tests in Hudson via JUnit

Perl tests in Hudson

I'm willing to automate the unit testing of my Perl modules, by plugging them into Hudson. Hudson is a continuous integration server, it "monitors executions of repeated jobs, such as building a software project or jobs run by cron". It works well, is extensible, and looks good.

So, The easiest way to do that is have Hudson to execute the module test suite, and look at the output. Actually, not really the output, but a file containing the output of the tests, in JUnit format.

Now, by default, Perl unit tests doesn't output JUnit. You know, that kind of stuff :

That's the standard output of tests run through TAP, the Test Anything Protocol, which is great, and (imho) better than JUnit.

Anyway, that output is generated because the tests are run through TAP::Harness, that outputs the result in TAP format on the console.

So first of all, let's see how to transform the tests output into JUnit. My modules use Module::Build (and also Dist::Zilla, but that's an other story) as building and releasing system. When using Module::Build, running the test suite is easy :

Solution 1 : use TAP::Formatter::JUnit

After some research and looking in the source code, I discovered that you can pass a lot of options to TAP::Harness, via Module::Build. Especially, you can specify a formatter to TAP::Harness when running the test suite. TAP formatters are modules that all inherit of TAP::Formatter::Base.

For instance, if instead of outputing the result on the console, you want it to be stored in a file, use TAP::Formatter::File. As you may have guessed now, there is a formatter that outputs JUnit : TAP::Formatter::Junit. That's exactly what we want. By issuing the following command line, the output of the test suite is in JUnit format.

Now we just need to tell Hudson to run it and look at the output

Solution 2 : use TAP::Harness::JUnit

For some reasons, I had some trouble with TAP::Formatter::Junit on windows, mainly because there is no ActiveState PPM for this package. So I decided to give a go with TAP::Harness::JUnit

Its documentation is self-explanatory : it's a child class of TAP::Harness, that accepts an xml file name as argument, and procudes directly a JUnit output. This module being directly available in ActiveState Perl, it seemed to be aa good approach.

So the goal is to replace the call to TAP::Harness into TAP::Harness::JUnit, when doing Build test. And actually, it would be better to have an additional action to Build, so that we could do Build test, and Build hudson_test.

Luckily, Module::Build makes it easy to add an action. By looking at the ACTION_test method in Module::Build::Base, it's easy to see what needs to be changed. See this code snippet. What we want is a copy of that code that would run TAP::Harness::JUnit instead of TAP::Harness.

After some work, here is what I eneded with. This code is to be added into your Build.PL.

Now, build and run your tests in hudson mode

Configure Hudson

That's the easiest part : Setup a new project, add as execution line "perl Build.PL & Build hudson_test" (if you are on a windows hudson node). And point the project to the output file called "hudson_test_output.xml". That's it !

Curses::Toolkit is on CPAN

After few months of delay, Curses::Toolkit is now available on CPAN.

Curses::Toolkit tries to be a modern toolkit to implement semi-graphical interfaces using Curses. It's inspired by Gtk.

I gave a presentation of Curses::Toolkit at the French Perl Workshop 2009, and at the Open Source Developers conference France 2009. BooK presented it as part of a Lightning Talk at YAPC EU 2009 where I couldn't participate. Thanks to him for that. I will try to participate to London Perl Workshop this year and give a talk about it as well. I have received quite good feedback from people and users about it.

I'd like to mention that Jerome Quelin helped me with the initial release, injecting some Dist::Zilla magic into Curses::Toolkit. Thanks, Jerome.

What next ? I'll try to post a video of what is currently possible with Curses::Toolkit. I need to add more widgets and signals, and fix some bugs. Also, migrating to Moose is on the todo list. The module is usable now, but you can't really build a very nice big application with it.

Want to help ? If you have some free time, please consider helping me on next development of the module. You don't need to be a coder, here are some of the things you could help with :

• Improve documentation : current documentation has some errors, and a better front page for the module would be good.
• Create a Tutorial : preferably in POD, but not tied to follow sub-modules' names
• Help implementing additional widgets
• Create new themes : it's all about colors
• Help the migration to Moose

If you're interested, contact me. The source is here

New Home

The new server I had setup few weeks ago got hacked, brute force ssh attacks being made from it... I had spent some time setting it up, and now I'm bored.

So, I decided to migrate my blog to a hosted solution. As I'm a big fan of movable type, I decided to give Typepad a go. So this is yet another rebirth of my blog (I think it's the 6th time now).

I'll use that opportunity to catch up with the Perl blogging Iron Man competition.

More to come about Perl and Curses::Toolkit, my baby :)